Emission modules for an optical signal transmission are known in which a laser diode is assigned a monitor photodiode which detects a part of the light emitted by the laser diode and serves for monitoring the laser diode. In particular, it is known, in order to realize a monitor function in VCSEL (Vertical Cavity Surface Emitting Laser) laser diodes, in which the resonator is situated vertically on the surface of a chip, to use reflective areas which project a part of the laser light onto a monitor diode. In this case, the laser diode may also be positioned on the monitor diode itself.
Furthermore, bidirectional emission/reception modules are known which, for the bidirectional transmission of data, simultaneously couple optical radiation into a waveguide and detect light power guided in the waveguide. Beam splitters with wave-selective filters and also a lens coupling optical arrangement are used for decoupling the emission device and the reception device in an emission/reception module of this type.
U.S. Pat. No. 6,005,262 discloses an arrangement in which a vertically emitting laser (VCSEL) is arranged in a flip-chip arrangement directly on a CMOS circuit. The CMOS circuit has a detector which detects a part of the laser light which is emitted at the rear side.